Australian Energy Market Operator

AEMO operates Australia's National Electricity Market (NEM), the interconnected power system in Australia’s eastern and south-eastern seaboard, and the Wholesale Electricity Market (WEM) and power system in Western Australia.

AEMO operates gas retail markets in New South Wales and the Australian Capital Territory, Queensland, South Australia, Victoria, and Western Australia. AEMO also operates wholesale gas markets in south-eastern Australia, those being the Declared Wholesale Gas Market in Victoria (DWGM), the Short Term Trading Market in Adelaide, Brisbane and Sydney (STTM), and the Gas Supply Hub (GSH), whose trading locations are based at Wallumbilla in Queensland, and Moomba in South Australia. AEMO also operates the Natural Gas Services Bulletin Board (GBB), and is system operator of the Victorian Gas Declared Transmission System. AEMO is also responsible for Gas Services Information functions in Western Australia.

Constraint Automation - Closing the Loop - Discussion Paper

Constraint Automation - Closing the Loop - Discussion Paper

The constraint automation is a software application in AEMO’s energy management system (EMS) that automatically generates thermal overload constraint equations based on the current or planned state of the power system. These constraint equations follow the constraint formulation guidelines as applied to manually constructed thermal overload constraint equations. Currently the constraint automation requires several manual steps to create and invoke constraint equations.

This discussion paper details how AEMO plans to remove the manual steps and allow the constraint automation to operate in “closed loop” mode, in the dispatch timeframe, such that the creation, updating and invocation of constraint equations is fully automated. In future stages AEMO plans to allow further automation of the process moving through 5 minute Pre-dispatch, 30 minute Pre-dispatch and potentially the PASA timeframes.

AEMO’s planned implementation timetable for the third stage of the constraint automation is:

Tuesday 9 April 2013:

Enable sending of Constraint Automation constraint equations to the electricity market systems for a single contingency / monitored line per region only

AEMO’s electricity control room to invoke the CA_AUTO constraint set

Tuesday 7 May 2013:

Enable a larger group of contingencies (4 to 5 per region) to be covered by Constraint Automation

June 2013:

Enable AEMO’s control room to be able to activate new contingencies via the auto list functionality

The constraint equations created by the constraint automation will be invoked via the CA_AUTO constraint set. The constraint equations will have consistent constraint equation IDs for the same monitored line and tripped line (see the plain English examples in Appendix 1 of the discussion paper).

The existing manually constructed dispatch constraint equations will be run in parallel for a period of time after the system is operational. The dispatch RHSs will then be progressively removed from the manually built thermal overload constraint equations.

Constraint Automation does not currently create pre-dispatch RHSs in real time. The manually built pre-dispatch and PASA RHSs will therefore be retained.

The Constraint Automation is currently active in AEMO’s pre-production systems and constraint equation results and changes can be viewed there.